49. The arm of an ancient half-bird, half-reptile animal 144

50. Diagram to illustrate the principle of heredity 156




THE STORY OF THE LIVING MACHINE.


INTRODUCTION.

==Biology a New Science==.--In recent years biology has been spoken of as
a new science. Thirty years ago departments of biology were practically
unknown in educational institutions. To-day none of our higher
institutions of learning considers itself equipped without such a
department. This seems to be somewhat strange. Biology is simply the
study of living things; and living nature has been studied as long as
mankind has studied anything. Even Aristotle, four hundred years before
Christ, classified living things. From this foundation down through the
centuries living phenomena have received constant attention. Recent
centuries have paid more attention to living things than to any other
objects in nature. Linnæus erected his systems of classification before
modern chemistry came into existence; the systematic study of zoology
antedated that of physics; and long before geology had been conceived in
its modern form, the animal and vegetable kingdoms had been comprehended
in a scientific system. How, then, can biology be called a new science
When it is older than all the others?

There must be some reason why this, the oldest of all, has been recently